1. Field of the Invention
The present invention relates to exposure apparatuses, exposure methods, device manufacturing methods, and carrier methods, and more particularly, to an exposure apparatus and an exposure method used in a lithography process to produce electronic devices such as a semiconductor device and the like, a device manufacturing method using the exposure apparatus, and a carrier method suitable to carry an object subject to exposure in the exposure apparatus.
2. Description of the Background Art
Conventionally, in a lithography process for manufacturing electron devices (microdevices) such as semiconductor devices (such as integrated circuits) and liquid crystal display devices, exposure apparatuses such as a projection exposure apparatus by a step-and-repeat method (a so-called stepper) and a projection exposure apparatus by a step-and-scan method (a so-called scanning stepper (which is also called a scanner) are mainly used.
Substrates such as a wafer, a glass plate or the like subject to exposure which are used in these types of exposure apparatuses are gradually (for example, in the case of a wafer, in every ten years) becoming larger. Although a 300-mm wafer which has a diameter of 300 mm is currently the mainstream, the coming of age of a 450 mm wafer which has a diameter of 450 mm looms near. When the transition to 450 mm wafers occurs, the number of dies (chips) output from a single wafer becomes double or more the number of chips from the current 300 mm wafer, which contributes to reducing the cost. In addition, it is expected that through efficient use of energy, water, and other resources, cost of all resource use will be reduced.
Meanwhile, when the size of the wafer becomes as large as 450 mm, while the number of dies (chips) output from a single wafer increases, a risk occurs of throughput deceasing due to an increase in the time required to perform an exposure process on a single wafer. Therefore, as a method of improving throughput as much as possible, employing a twin stage method can be considered where an exposure process on a wafer is performed on one wafer stage, and processing such as wafer exchange, alignment or the like is performed concurrently on another wafer stage, as is disclosed in, for example, U.S. Pat. No. 7,161,659, U.S. Pat. No. 6,590,634, U.S. Pat. No. 6,208,407, or U.S. Pat. No. 5,969,441 and the like.
However, the 450 mm wafer has a characteristic of being larger and thinner when compared to the 300 mm wafer. Therefore, appearance of a technology related to exposure apparatuses that could be suitably applied not only to conventional sized wafers such as the 300 mm wafer, but also to the 450 mm wafer, and could contribute to maintaining or improving the throughput, and/or reducing the running cost, especially a new technology related to wafer carriage (including movement at the time of exchange), was expected.